Have you ever wondered how many years it would it take to double your money? I am assuming your principal sum is compounded annually in order for this formula to work. I am no genius or expert but I did discover this formula quite accidentally while doing some calculations and I haven't found it in any text book.It is probably there, but I haven't found it.

If you invest any principal amount at 5% it will take 14.20669908 years to double your money. Watch this: ln 2 divided by ln 1.05 =

14.20669908 years. "ln"" mean natural log . Now if you have a calculator you don't have to know anything else about it.

You simply press ln and then 2 and divide by ln 1.05. (You must remember that 5% = .05 and that you have to insert a 1 before it to represent the principal.) Otherwise it won't work.

For example : how many years would it take to double your money ( any sum) if you compounded it at 10% per annum. Answer 7.275 years.

Moving right along: the other day I was at the bank and they were giving me 1.5% over 18 months (simple interest in this case ) on the $50,000 we invested some time ago. I was an absolute idiot to accept it I should have put it into Canadian bank stocks but didn't because I was apprehensive about having enough money for urgent needs in case I had a financial problem - I didn't has it happened.

Now imagine how long it would take to double your money at an annual compounding rate of 1.5% ( forget the complexity of it not being offered or that they offered it as simple interest over 18 months which complicates matters as they really gave us 12/18th of 1.5% which is .06666.% per year ) what a bank !

Now it takes over 46 years to double your money if compounded annually at 1.5%. (46.55552563 years to be more exact

(ln2 /ln1.015 = 46.55552563 years)

EDIT.

To check that 46.5552653 is the doubling time if $1 is invested at a1.5% interest rate compounded annually.

Do this:

On your calculator enter 1.015 to the power of 46.55552563 and you should get 2 or $2.

Enter 1.015 ,then press the y to x key on your calculator and enter the power of 46.55552563 and the answer should be 2.That is the proof of the doubling theory of ln2/ln1.015. And so it is

Let nothing disturb you.

Let nothing make you afraid.

All things are passing.

God alone never changes.

Patience gains all things.

If you have God you will want for nothing.

God alone suffices.

— St. Teresa, The bookmark of Teresa of Ávila, [28]